NS2.CPS.COM.AR has no CNAME records.
Question and response
Question
dig NS2.CPS.COM.AR. NS
Answer
The response has no answer records.
Authority
cps.com.ar. 4170 SOA ns1.cps.com.ar. hostmaster.cps.com.ar. 2006092996 3600 900 2419200 43200
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0